MEG0024 Use of Elements and Attributes
Version: 0.02
Last Updated: 3/19/2009
Status: Ready For Governance Review
Purpose
P1. Purpose
P1.1 Introduction
The Version 3.0 Reference Model is element-centric; the data being communicated is carried at the element-level as opposed to the attribute-level. The containers are also defined at the element-level. However, there is also information that is carried at the attribute-level. This MEG describes when to use elements and when to use attributes.
P1.2 Audience
This MEG was written for the following groups:
- MISMO Workgroup members developing MISMO messages.
- Designers and users of systems that create and consume the XML instance documents used in Real Estate Finance transactions.
- Technical or business professionals wishing to evaluate MISMO specifications.
P1.3 Terminology
The key words “MUST”, “MUST NOT”, “REQUIRED”, “SHOULD”, “SHOULD NOT”, “RECOMMENDED”, “MAY”, and “OPTIONAL” in this document are to be interpreted as described in RFC 2119
.
- MUST - This word, with the term “REQUIRED”, indicates an absolute requirement of the specification.
- MUST NOT - This phrase indicates an absolute prohibition of the specification.
- SHOULD - This word, or the adjective “RECOMMENDED”, means that there may exist valid reasons in particular circumstances to ignore a particular item, but the full implications must be understood and carefully weighed before choosing a different course.
- SHOULD NOT - This phrase, or the phrase “NOT RECOMMENDED” means that there may exist valid reasons in particular circumstances when the particular behavior is acceptable or even useful, but the full implications should be understood and the case carefully weighed before implementing any behavior described with this label.
- MAY - This word, or the adjective “OPTIONAL”, indicates that the specification allows the designer to choose whether or not to comply.
P1.4 Assumptions
The information supplied in this document reflects the MISMO architecture development and interoperability principles at the time of writing. It is a living document, which will be updated as required to reflect the evolving nature of XML technologies and service requirements identified by the MISMO constituency.
Content
C1. Content
C1.1 Guidelines
| Ref |
Guideline |
| 24.1 |
ALL MISMO containers MUST be defined as elements. Containers will be defined in all upper case with underscores representing whitespace. |
| 24.2 |
All data points MUST be defined as elements except for the noted exceptions in the Engineering Guidelines. Data points will be defined in upper camel case with no whitespace. |
| 24.3 |
The following exceptions have been defined that indicate data MAY be included as an attribute: |
| 24.3.1 |
All multi-instance containers MUST have an attribute that designates sequence order. This attribute will be called “SequenceNumber” and will be defined as MISMONumeric. |
| 24.3.2 |
All items occurring in the Xlink namespace MUST be represented as attributes. Each container in the reference model will have an attribute group associated with it to manage the Xlink attributes. |
| 24.3.3 |
To capture additional metadata on certain data points, several MISMO defined data types MAY include attribute children |
| 24.3.3.1 |
MISMOAmount MAY include an attribute child of “CurrencyURI”. This attribute allows for the designation of a specific currency for the amount being communicated. If this attribute is not included, it is assumed to be US dollars. It is recommended that the values communicated in CurrencyURI be based on the ISO 4217. |
| 24.3.3.1 |
MISMOCode MAY include two attribute children, “CodeOwnerURI” and “CodeEffectiveDate”. The attributes allow for the identification of the code’s owner and the effective date for the actual code (to handle multiple iterations of codes that can be passed through the lifecycle of the loan). |
| 24.3.4 |
MISMOIdentifier MAY include two attribute children, “IdentifierOwnerURI” and “IdentifierEffectiveDate”. The attributes allow for the identification of the identifier‘s owner and the effective date for the identifier (to handle multiple iterations of identifiers that can be passed through the lifecycle of the loan). |
C2. Additional Information
Metadata
M1. Metadata
| Element |
Description |
| Title |
Use of Elements and Attributes |
| Identifier |
MEG0024 |
| Category |
Foundation |
| Date Created |
03/11/2009 4:15:00 pM |
| Last Updated |
03/19/2009 6:27:00 PM |
| Publisher |
MISMO |
| Copyright |
©2009 MISMO. All Rights Reserved. |
M1.1 Release History
| Release Date |
Version No. |
Comments |
| 3/11/2009 |
0.01 |
Initial Version |
| 3/12/2009 |
0.02 |
Update based on 3/12 D3 call |
M1.2 Known Issues or Omissions
None.
| Name |
Organization |
Contact Details |
| MISMO Staff |
MISMO |
info@mismo.org |
M1.4 References
Comments
None.
T1. Terms and Conditions
T1.1 Disclaimer
MISMO accepts no liability for the accuracy, adequacy, or completeness of the information contained in this MISMO Engineering Guideline (MEG).
T1.2 Reproduction
Material in this MEG may be reproduced free of charge without obtaining explicit permission from MISMO, provided that the source is acknowledged, the document title given, and the material is used in context.
T1.3 Copyright
©2009 MISMO. All material in this MEG is the property of MISMO. All Rights Reserved.